The present invention relates generally to belt type conveyor systems for sorting and conveying flat documents on-edge and equipped with diverter mechanisms for diverting documents from a primary document path to one of at least two secondary document paths, and more particularly to a secondary pivotal drive stacker roller for use with such a sorting conveyor system to facilitate the advancement of shorter length documents along each secondary document path towards a stacker station.
Conveying systems are generally known which convey and sort documents, such as mailing envelopes and the like, on-edge along a primary or main path from which the documents may be selectively diverted or sorted according to predetermined criteria such as their particular mailing zone destination. The primary conveyor paths of such systems are generally defined at least in part by a rectilinear, vertically disposed run of a primary endless conveyor belt.
One or more document diverter or sorter stations are supported along the length of the primary conveyor belt, and each includes a secondary conveyor belt having a run inclined to the primary conveyor path, and along which a document travels when diverted from the primary conveyor path. Such document diverter stations may employ a switching roller disposed transverse to the primary conveyor belt and which is movable to push the primary belt in a direction to cause a document to deviate from the primary or main conveyor path to a secondary or branch route. Other diverter stations employ pivotally mounted diverter vanes.
One disadvantage of such sorting and conveying systems, especially those systems adapted to sort and convey non-letter sized mail, including large sized envelopes and magazines, also known as "flats", is that the arrangement of a secondary conveyor belt designed to accept flats diverted from the main document path is often incapable of rapidly processing letter sized mail, which is relatively shorter in length. In such systems, the letter sized mail may become jammed in the belts, disrupting the document sorting process. This disadvantage is especially noticeable when stacks of uniformly dimensioned letter sized mail are to be sorted.
Thus, an object of the present invention is to provide a document sorting apparatus designed to accommodate letter sized mail, as well as flats.
Another object of the present invention is to provide a device for use with a document sorting apparatus which enables the apparatus to be readily converted from sorting uniform stacks of flats to sorting uniform stacks of letter sized mail.
Still another object of the present invention is to provide a device for use with a document sorting apparatus which automatically adapts the apparatus to sort either letter sized mail or flats.